1. Field of the Invention
This invention relates generally to optical sensors that employ fiber-optics, and more specifically to holographic processors that are utilized in such sensor systems.
2. Prior Art
Conventional sensor systems which include sensors adapted to measure various physical characteristics of a sample, typically provide an analog output signal. Consequently, should a digital representation of an output signal be desired, relatively expensive and space consuming analog-to-digital equipment is required. Moreover, such conventional analog sensors are limited in application because of their inherently large size and slow response time. Moreover, either complex transmission lines or signal conversion apparatus may be required when the sensor must collect information from a remote sample. Hence, prior art transmission systems that have heretofore been interfaced with sensors of the prior art are relatively expensive to fabricate, are not capable of carrying sufficiently wide bandwidth signals, lack immunity to electro-magnetic and/or electric static interferences and require numerous interfacing apparatus.
There are prior art devices that are known to those skilled in the art which are generally adapted to optically decode information that is transmitted by means of incident light beams in order to measure various physical parameters (such as temperature, pressure, etc.). It is generally well known that it is preferable to provide means for transmitting and utilizing signals representative of such physical parameters in a digital format to enhance the accuracy of the transmission and also to provide signals that are compatible with modern microprocessor controlled systems for utilizing the sensor signals. An example of an optical sensor system that utilizes a fiber optic transmission apparatus to provide accurate digital representations of a physical parameter from a remote sample can be found in U.S. Pat. No. 4,223,226 issued Sept. 16, 1980. However, nothing is known in the prior art which shows or suggests the use of holographic processors in such sensor systems. In particular, there is no known prior art which uses holographic processors for enhancing the utilization of optical signals in such a system by enabling multiplexing and demultiplexing of such optical signals, or for that matter, conversion of optical signals directly into any one of a number of digital formats as hereinafter disclosed and which even further reduce the cost and complexity of optical sensor systems.